MEMS device

Abstract

A MEMS device includes a fixed electrode and a movable electrode arranged isolated and spaced from the fixed electrode by a distance. The movable electrode is suspended against the fixed electrode by one or more spacers including an insulating material, wherein the movable electrode is laterally affixed to the one or more spacers.

The invention claimed is: 
     
       1. A MEMS device, comprising:
 a fixed electrode; and 
 a movable electrode arranged isolated and spaced from the fixed electrode by a distance; 
 wherein the movable electrode is suspended against the fixed electrode by two or more spacers comprising an insulating material, wherein the movable electrode is laterally affixed to the two or more spacers, and 
 wherein the two or more spacers are separated from each other by an opening extending along the movable electrode. 
 
     
     
       2. The MEMS device according to  claim 1 , wherein the movable electrode has a square shape and wherein the movable electrode is suspended at one or more corners of the movable electrode via the two or more spacers, respectively. 
     
     
       3. The MEMS device according to  claim 1 , wherein the two or more spacers are embedded in the movable electrode. 
     
     
       4. The MEMS device according to  claim 1 , wherein the two or more spacers comprise an oxide or nitride. 
     
     
       5. The MEMS device according to  claim 1 , wherein the two or more spacers have a different material or a different grid structure when compared to a material or a grid structure of the movable electrode. 
     
     
       6. The MEMS device according to  claim 1 , wherein a footprint of the two or more spacers is at least 10 times smaller when compared to a footprint of the movable electrode. 
     
     
       7. The MEMS device according to  claim 1 , wherein the distance between the fixed electrode and the movable electrode is variable and wherein a variation of the distance leads to a variation of a capacitance. 
     
     
       8. The MEMS device according to  claim 1 , wherein the movable electrode is electrically contacted via a conductor arranged at one of the two or more spacers. 
     
     
       9. The MEMS device according to  claim 1 , wherein the fixed electrode is formed by or attached to a substrate. 
     
     
       10. The MEMS device according to  claim 9 , wherein the two or more spacers have a material having a reduced thermal conductivity when compared to a material of the movable electrode or of the substrate. 
     
     
       11. The MEMS device according to  claim 10 , wherein the MEMS device forms a bolometer. 
     
     
       12. The MEMS device according to  claim 1 , wherein the movable electrode is formed as a cantilever. 
     
     
       13. The MEMS device according to  claim 12 , wherein the MEMS device forms an acceleration sensor or a humidity sensor. 
     
     
       14. The MEMS device according to  claim 1 , wherein a further spacer is arranged in an area of the opening in order to hermetically close a cavity below a membrane formed by the movable electrode. 
     
     
       15. The MEMS device according to  claim 14 , wherein the MEMS device forms a pressure sensor. 
     
     
       16. A MEMS device, comprising:
 a substrate comprising a fixed electrode; and 
 a movable electrode arranged isolated and spaced from the fixed electrode by a distance, the movable electrode having a square shape; 
 wherein the movable electrode is suspended from the fixed electrode by one or more spacers comprising an insulating oxide at its corners, wherein the movable electrode is laterally affixed to the one or more spacers; 
 wherein the distance between the fixed electrode and the movable electrode is variable and wherein a variation of the distance leads to a variation of a capacitance. 
 
     
     
       17. A method for manufacturing a MEMS device, comprising:
 providing a sacrificial layer over a fixed electrode; 
 providing a movable electrode over the sacrificial layer such that a layer stack comprising the sacrificial layer and the movable electrode is formed; 
 providing one or more spacers comprising an insulating material adjacent to the layer stack such that the movable electrode is laterally affixed to the one or more spacers; 
 defining the area of the layer stack by using lithography and/or anisotropic etching before providing the one or more spacers; and 
 removing the sacrificial layer at least in a portion aligned with a portion of the movable electrode such that the movable electrode is spaced from the fixed electrode by a distance that is related to a thickness of the sacrificial layer; 
 wherein the movable electrode is suspended from the fixed electrode by the one or more spacers. 
 
     
     
       18. The method according to  claim 17 , wherein defining the area of the layer stack comprises forming at least one hole in the layer stack for the one or more spacers, and
 wherein the one or more spacers are embedded in the movable electrode. 
 
     
     
       19. The method according to  claim 17 , wherein removing the sacrificial layer is performed in a portion where the fixed electrode is aligned with the entire movable electrode. 
     
     
       20. The method according to  claim 17 , wherein an etch rate of the sacrificial layer differs from an etch rate of the spacer. 
     
     
       21. The method according to  claim 17 , wherein providing the one or more spacers comprises providing two or more spacers, and wherein providing two or more spacers is performed such that an opening is formed in between. 
     
     
       22. The method according to  claim 21 , wherein removing the sacrificial layer comprises etching or isotropic etching through the opening. 
     
     
       23. The method according to  claim 21 , further comprising closing the opening by a further spacer after removing the sacrificial layer. 
     
     
       24. The method according to  claim 17 , wherein providing the one or more spacers comprises anisotropic etching and/or using lithography in order to limit a footprint of the one or more spacers. 
     
     
       25. The method according to  claim 24 , wherein the anisotropic etching and/or using lithography is performed such that the footprint of the one or more spacers is at least 10 times smaller than a footprint of the movable electrode.